1. Field of the Invention
The present invention relates to an optical filter manufacturing apparatus, and more particularly, to a mask having a curved shape having predetermined openings and an optical filter manufacturing apparatus including the same, which have a high patterning precision irrespective of a distance between the mask and a base film, and are applicable to a roll-to-roll process.
2. Discussion of Related Art
In recent years, a technique of aligning light by irradiating an alignment layer of a liquid crystal display (LCD) or a viewing angle compensation base film layer with polarized light having a predetermined wavelength, using a method of providing alignment performance to the alignment layer, has widely been used. Conventionally, combinations of a rod-shaped lamp, which is a linear light source, with a wire grid polarizer (WGP) as described in Korean Patent Publication No. 2006-0053117 and Korean Patent Publication No. 2009-0112546 have been used as polarized light radiation devices for light alignment layers.
The light alignment technique has been scaled up with the scaling-up of liquid crystal (LC) panels. Thus, a light irradiation region having a larger area has been irradiated at a higher luminance by a light radiation device configured to radiate polarized light at the light alignment layer.
To irradiate a large area with light at a high luminance, a light source of the light radiation device should be scaled up accordingly. Since a direction of polarized light that determines alignment is dependent on the incidence angle of incident light, when the light source is scaled up, nonuniformity in incidence angle occurs in the light irradiation region, thus resulting in nonuniformity in a polarization axis. As a result, an alignment direction is not uniform according to an irradiation region so that light may be aligned in an undesired direction.
Furthermore, in a roll-to-roll process, there are many cases where light irradiation regions have curved surfaces. In these cases, as the area of the light irradiation regions increases, nonuniformity in a polarization axis caused by the curved surfaces may become more problematic in the light irradiation regions.
To obtain a uniform polarization distribution over a large area, highly collimated light should be incident on a polarization device. A large apparatus is required to generate highly collimated light corresponding to a large area. Since the intensity of light decreases as the length of a light path of the apparatus increases, a processing time increases, thus degrading productivity. In conclusion, to generate collimated light, it is difficult to embody optical properties without the enlarging apparatus. As a result, a roll-to-roll process cannot be performed, thereby resulting in a remarkable drop in productivity.